The film transducer can be used for converting electrical energy to mechanical work. It is, for example, known to utilize it as an actuator.
A conventional design of such film transducer uses a holding part, an electroactive composite structure including at least one deformable carrier and at least two electrodes arranged on opposite sides of the deformable carrier, and a load application member mounted to the electroactive composite structure.
In simplified terms, the electroactive composite structure consists of an elastically deformable dielectric medium in the form of a thin film which serves as a carrier for the two electrodes. The electrodes are mounted to the upper and lower sides of the film. When an electric field is generated between the two electrodes, an attractive force is produced between the electrodes, so that they seek to reduce the distance between them. This causes the carrier to be pressed together. Since the material of the carrier is essentially incompressible, a reduction in thickness of the carrier results in an increase in its length. This may generate a stroke of the load application member, for instance when it is urged into a specific direction by a spring.
In the prior art, the holding part is usually in the form of a closed ring or frame enclosing the composite structure on all sides. In a top view, for example, this frame and the carrier may have a circular shape or a rectangular shape. It has been found that this is not an optimum shape for the holding part for various applications.
It is the object of the invention to improve the known film transducer in such a way as to produce a better adjustment behavior of the load application member.